Actuators are used in myriad devices and systems. For example, many vehicles including, for example, aircraft, spacecraft, watercraft, and numerous other terrestrial and non-terrestrial vehicles, include one or more actuators to effect the movement of various components. No matter the specific end-use, actuators are many times classified based on the power source that is used to effect actuation. For example, actuators are many times classified as hydraulic-, pneumatic-, or electrically-operated (or electromechanical) actuators.
Electromechanical actuators typically include an electric motor that is used to supply a drive torque to an actuated element, such as a valve. In many instances, it is desirable to convert the rotation of electric motor to linear movement to move the actuated element in a linear direction. For example, in the context of a projectile, it may be desirable to selectively move a pintle valve in a linear direction to effect attitude control. In such contexts, it is additionally desirable to physically implement an electromechanical actuator that has a relatively small size and low weight. In the past, these goals have been met by using a relatively small electric motor that rotates at a relatively high rotational speed, and then including some type of gear reduction to increase the output torque of the actuator.
Although the above-described approach generally works well, it does exhibit certain drawbacks. For example, the gear reduction that may be needed to achieve the desired torque output may cause the size and/or weight of the actuator to be higher than desired. Moreover, in some instances, the electromechanical actuators do not exhibit a sufficient level of precision and/or exhibit excessive backlash.
Hence, there is a need for an electromechanical actuator that includes a small, high speed motor with sufficient gear reduction that has a relatively small space envelope and/or relatively smaller weight as compared to known electromechanical actuator configurations, and/or exhibits relatively high precision and/or does not exhibit excessive backlash. The present invention addresses one or more of these needs.